Discontinuous reception start offset coordinated with semi-persistent scheduling system and method

ABSTRACT

An apparatus and method are provided for configuring a user agent to receive semi-persistent scheduling (SPS) transmissions independent of the user agent monitoring a physical downlink control channel (PDCCH). Also provided are an apparatus and method for configuring a user agent to monitor a PDCCH in a subframe to which one of a downlink assignment or an uplink grant is configured.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/618,198 filed Sep. 14, 2012 by Takashi Suzuki, et al. entitled,“Discontinuous Reception Start Offset Coordinated with Semi-PersistentScheduling System and Method” which is a continuation of U.S. Pat. No.8,295,240 issued on Oct. 23, 2012 entitled, “Discontinuous ReceptionStart Offset Coordinated with Semi-Persistent Scheduling System andMethod” which claims priority to U.S. Provisional Application No.61/149,226 filed Feb. 2, 2009; U.S. Provisional Application No.61/162,594 filed Mar. 23, 2009; U.S. Provisional Application No.61/169,645 filed Apr. 15, 2009; and U.S. Provisional Application No.61/172,979 filed Apr. 27, 2009, which are incorporated by referenceherein as if reproduced in their entirety.

BACKGROUND

As used herein, the terms “user agent” and “UA” might in some casesrefer to mobile devices such as mobile telephones, personal digitalassistants, handheld or laptop computers, and similar devices that havetelecommunications capabilities. Such a UA might consist of a UA and itsassociated removable memory module, such as but not limited to aUniversal Integrated Circuit Card (UICC) that includes a SubscriberIdentity Module (SIM) application, a Universal Subscriber IdentityModule (USIM) application, or a Removable User Identity Module (R-UIM)application. Alternatively, such a UA might consist of the device itselfwithout such a module. In other cases, the term “UA” might refer todevices that have similar capabilities but that are not transportable,such as desktop computers, set-top boxes, or network appliances. Theterm “UA” can also refer to any hardware or software component that canterminate a communication session for a user. Also, the terms “useragent,” “UA,” “user equipment,” “UA,” “user device” and “user node”might be used synonymously herein.

As telecommunications technology has evolved, more advanced networkaccess equipment has been introduced that can provide services that werenot possible previously. This network access equipment might includesystems and devices that are improvements of the equivalent equipment ina traditional wireless telecommunications system. Such advanced or nextgeneration equipment may be included in evolving wireless communicationsstandards, such as long-term evolution (LTE). For example, an LTE systemmight include an enhanced node B (eNB), a wireless access point, or asimilar component rather than a traditional base station. As usedherein, the term “access node” will refer to any component of thewireless network, such as a traditional base station, a wireless accesspoint, or an LTE eNB, that creates a geographical area of reception andtransmission coverage allowing a UA or a relay node to access othercomponents in a telecommunications system. In this document, the term“access node” may comprise a plurality of hardware and software.

An LTE system can include protocols such as a Radio Resource Control(RRC) protocol, which is responsible for the assignment, configuration,and release of radio resources between a UA and an access node or relaynode or other LTE equipment. The RRC protocol is described in detail inthe Third Generation Partnership Project (3GPP) Technical Specification(TS) 36.331. According to the RRC protocol, the two basic RRC modes fora UA are defined as “idle mode” and “connected mode.” During theconnected mode or state, the UA may exchange signals with the networkand perform other related operations, while during the idle mode orstate, the UA may shut down at least some of its connected modeoperations. Idle and connected mode behaviors are described in detail in3GPP TS 36.304 and TS 36.331.

The signals that carry data between UAs, relay nodes, and access nodescan have frequency, time, and coding parameters and othercharacteristics that might be specified by a network node. A connectionbetween any of these elements that has a specific set of suchcharacteristics can be referred to as a resource. The terms “resource,”“communications connection,” “channel,” and “communications link” mightbe used synonymously herein. A network node typically establishes adifferent resource for each UA or other network node with which it iscommunicating at any particular time.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a block diagram of a mobile communications system suitable forimplementing the several embodiments of the present disclosure.

FIG. 2 is a timing diagram illustrating simultaneous operation ofsemi-persistent scheduling (SPS) and discontinuous reception (DRX) in auser agent (UA), according to the current state of the 3GPPspecifications.

FIG. 3 is a timing diagram illustrating simultaneous operation of SPSand DRX in a UA, according to an embodiment of the disclosure.

FIG. 4 is a timing diagram illustrating simultaneous operation of SPSand DRX in a UA, according to an embodiment of the disclosure.

FIG. 5 is a timing diagram illustrating simultaneous operation of SPSand DRX in a UA, according to an embodiment of the disclosure.

FIG. 6 is a flowchart illustrating a method of receiving using aconfigured DL assignment, according to an embodiment of the disclosure.

FIG. 7 is a flowchart illustrating a method of receiving using aconfigured DL assignment, according to an embodiment of the disclosure.

FIG. 8 is a flowchart illustrating a method of adjusting DRX timing andreceiving using a configured DL assignment, according to an embodimentof the disclosure.

FIG. 9 is a flowchart illustrating a method of adjusting DRX timing andreceiving using a configured DL assignment, according to an embodimentof the disclosure.

FIG. 10 is a flowchart illustrating a method of configuring a configureddownlink assignment, according to an embodiment of the disclosure.

FIG. 11 is a flowchart illustrating a method of monitoring a physicaldownlink control channel (PDCCH), according to an embodiment of thedisclosure.

FIG. 12 is a flowchart illustrating a method of starting or restartingan on duration timer, according to an embodiment of the disclosure.

FIG. 13 is a flowchart illustrating a method of adjusting adiscontinuous reception (DRX) start offset, according to an embodimentof the disclosure.

FIG. 14 illustrates a processor and related components suitable forimplementing the several embodiments of the present disclosure.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrativeimplementations of one or more embodiments of the present disclosure areprovided below, the disclosed systems and/or methods may be implementedusing any number of techniques, whether currently known or in existence.The disclosure should in no way be limited to the illustrativeimplementations, drawings, and techniques illustrated below, includingthe exemplary designs and implementations illustrated and describedherein, but may be modified within the scope of the appended claimsalong with their full scope of equivalents.

As used herein, the following acronyms have the following definitions.

“Active time” refers to a time when a UA is monitoring the PDCCH.

“C-RNTI” is defined as “cell radio network temporary identifier,” whichrefers to an identifier for a UA.

“DL-SCH” is defined as “downlink shared channel.”

“DRX” is defined as “discontinuous reception,” in which a UA attempts toreceive data and/or resources only during certain times.

“eNB” is defined as “enhanced node B,” which is an example of one typeof access node or device used in a radio access network (RAN) to aid inestablishing communication between a UA and a Core Network (CN).

“HARQ” is defined as “hybrid automatic repeat request,” which refers toan error control method.

“LTE” is defined as “long term evolution,” which refers to a newersystem of high speed mobile communications and infrastructurestandardized by 3GPP.

“On duration time” or “on duration” refers to a time, which recursperiodically, when the UA monitors the PDCCH.

“PDCCH” is defined as “physical downlink control channel,” which refersto a channel over which a UA can be allocated uplink and/or downlinkresources, and over which SPS transmission can be activated or released.

“RTT” is defined as “round trip time.”

“SPS” is defined as “semi-persistent scheduling,” which refers to amechanism or technique whereby a UA can be configured with aperiodically recurring resource for downlink and/or uplink initialtransmission without that resource being indicated on the PDCCH everytime.

“TS” is defined as “technical specifications,” which are mobilecommunications specifications called-for by the 3GPP (3^(rd) generationpartnership project) for implementing an LTE system.

“TTI” is defined as “transmission time interval,” which refers to aperiod of time between instances when a transport block is madeavailable to the physical layer for transmission, or between instanceswhen a transport block may be received from the physical layer; a TTImay be referred-to as, for example, a subframe.

Other acronyms that may appear herein are used and defined according tothe technical specifications of the 3GPP standards. As used herein,terms within quotation marks refer to a name of an object or process.

The embodiments described herein relate to an issue that arises withregard to behavior of a UA during simultaneous operation of SPS and DRX.As described further below with respect to FIG. 2, the currentspecifications (TS36.321 version 8.5.0) describe that the UA does notreceive using a configured downlink assignment outside of the activetime of DRX. According to the specification, as the UA cannot receive aconfigured downlink assignment outside of the active time, thenconfigured downlink assignments would have to be configured in asubframe when the “on duration timer” is running. This arrangementensures reception of configured downlink assignments, even though theconfiguration is allowed whenever the UA monitors the PDCCH. However,because the active time duration depends on the activity of the UA, theUA may not be monitoring the PDCCH. Hence, the UA may fail to receivethe downlink assignment, which is configured outside of the “onduration” period. As a result, scheduling flexibility may be limited,which may lead to less efficient resource utilization. Additionally, thenetwork may attempt to change the timing of the downlink assignmentconfiguration outside of the “on duration” time in order tore-distribute the load on resources, or to align with new talk spurttime. These issues are further described with respect to FIG. 2.

This disclosure may address, in some embodiments, the issues describedabove. Several alternative embodiments are also provided herein. In oneembodiment, the UA uses a configured downlink assignment independent ofits PDCCH monitoring. Alternatively, the UA monitors the PDCCH in asub-frame to which a downlink assignment is configured. In these twoalternative embodiments, the UA receives its SPS transmissions evenwhere the SPS transmissions do not align with the “on duration” time.Thus, the UA has an extra occasion to be active, and the UA ultimatelyreceives more transmissions.

In another embodiment, the “on duration timer” is started or restartedwhen the starting condition is satisfied, thereby ensuring correct DRXoperation when the radio resource control (RRC) configures orreconfigures the DRX start offset. In some contexts, the DRX startoffset may be referred to as the DRX Start Offset. In yet anotherembodiment, the UA adjusts the DRX start offset when a downlinkassignment is configured or reconfigured. In another alternativeembodiment, the UA detects its SPS-RNTI during the active time, whenindicated by the network for a preconfigured duration; otherwise, the UAdetects its SPS-RNTI during the “on duration” period only. Thus, theembodiments provide for a user agent enabled to receive an SPStransmission using a configured downlink assignment independent of theuser agent monitoring a physical downlink control channel (PDCCH).

FIG. 1 is a block diagram of a mobile communications system 100 suitablefor implementing the several embodiments of the present disclosure.Mobile communications system 100 includes UA 102 and network 104. UA 102communicates with network 104, as shown by arrows 106. UA 102 can alsocommunicate with other telecommunications devices using network 104.

UA 102 can take many forms, as described above. Likewise, network 104can include one or more devices and/or software used intelecommunication systems. In an embodiment, network 104 represents anLTE system, though network 104 could be any number of devices ofdifferent networks. Network 104 can also include a radio access network(RAN), relays, eNBs, and many other devices for implementing atelecommunications network.

For purposes of the embodiments described herein, an “uplink” is acommunication that originates at the UA 102 and is directed towards thenetwork 104. Likewise, a “downlink” is a communication that originatesat the network 104 and is directed at the UA 102.

FIG. 2 is a timing diagram illustrating simultaneous operation ofsemi-persistent scheduling (SPS) and discontinuous reception (DRX) in auser agent (UA), according to the current state of the 3GPPspecifications. The aspects of FIG. 2 can be implemented in a UA, suchas UA 102 of FIG. 1.

Part of the operation of a UA involves receipt of communicationsresources from a network, such as network 104 of FIG. 1. In anembodiment, a UA receives such resources over a physical downlinkcontrol channel (PDCCH) that is transmitted by the network. One methodfor a UA to more efficiently receive resources over the PDCCH is to usesemi-persistent scheduling (SPS).

SPS is a technique in which the UA is configured with a resource on asemi-persistent basis for downlink and/or uplink initial transmissionswithout that resource being indicated on the PDCCH every time a resourceis to be used. Within the 3GPP specifications, as well as for thepurposes herein, the periodically recurring resource can be referred toas “configured downlink assignments” in the case of downlinks, and“configured uplink grants” in the case of uplinks.

In order to use the SPS mechanism, the access node sends the UA an SPSactivation command which includes the configured downlink assignment orthe configured uplink grant. The SPS activation command is sent to theUA on the PDCCH, and therefore can only be sent to the UA during theactive time when the UA is monitoring the PDCCH. The SPS activationcommand may be sent to the UA using an SPS-RNTI, which is an SPSspecific identifier for that UA. Once SPS is activated, the configureddownlink assignment and/or configured uplink grant is used by the UAuntil it is released, for example, by reception of an SPS releasecommand sent to the UA on the PDCCH. The timing of the configureddownlink assignments and/or configured uplink grants is based in part onthe time when the SPS activation command is received by the UA. In oneexample, the configured downlink assignment and/or configured uplinkgrant recurs periodically from the time of reception of the SPSactivation.

To conserve battery power, the UA may be configured to avoid continuousmonitoring of the PDCCH. In particular, the UA will monitor the PDCCHonly at given subframes. This type of monitoring may occur duringdiscontinuous reception (DRX), for example, to conserve battery power.During DRX the subframes in which the UA monitors the PDCCH, referred toas the “on duration,” recur periodically. The timing of the “ondurations” may be configured by the access node, for example, by sendinga parameter such as “DRX start offset” to the UA. Different UAs may beconfigured with different values of “DRX start offset” in order todistribute the UA's “on durations” in time.

As mentioned above, an issue that arises with regard to behavior of a UAduring simultaneous operation of SPS and DRX. The specifications(TS36.321 version 8.5.0) describe that the UA does not receive using aconfigured downlink assignment outside of the active time of DRX. Thecurrent specification, such as at section 5.3.1, currently calls for aparticular procedure with regard to reception using configured downlinkassignment.

In particular, the downlink assignments transmitted on the PDCCHindicate whether there is a transmission on the DL-SCH for a particularUA, and also provides the relevant HARQ information. When the UA has aC-RNTI, Semi-Persistent Scheduling C-RNTI, or Temporary C-RNTI, the UA,for each TTI during which it monitors PDCCH, takes one of severalpossible alternative actions. If a downlink assignment for a TTI hasbeen received on the PDCCH for the UA's C-RNTI, or Temporary C-RNTI,then a particular action is taken with regard to processing a downlinkassignment. Otherwise, if a downlink assignment for this TTI has beenreceived on the PDCCH for the UA's Semi-Persistent Scheduling C-RNTI,then processing of SPS release, activation, and other events may occur.If a downlink assignment for this TTI has been configured, then thephysical layer is instructed to receive, in this TTI, transport(s) blockon the DL-SCH according to the configured downlink assignment and todeliver it to the HARQ entity.

Thus, the UA does not receive using a configured downlink assignmentoutside of the active time when the UA monitors the PDCCH. However, theaccess node may choose to activate SPS at any time during the activetime. Because the active time duration depends on the activity of theUA, the UA may not be monitoring the PDCCH, and hence may fail toreceive using the configured downlink assignment if monitoring needs tooccur outside of the “on duration” period. This result is undesirable,because data transmissions sent using the configured downlink assignmentwill not be received, scheduling flexibility is limited, and resourceutilization is less efficient. FIG. 2 describes this situation in moredetail.

Generally, FIG. 2 represents events that occur as time moves forward inthe direction indicated by arrows 200, 202, and 204. The times alongarrow 200, arrow 202, and arrow 204 are aligned with each other. Arrow200 represents the occurrences of DRX “on duration” events. Arrow 202represents UA activity for the case in which downlink SPS is timealigned with the DRX “on duration.” Arrow 204 represents UA activity forthe case in which downlink SPS is not time aligned with the DRX “onduration.”

Thus, DRX “on duration” block 206, DRX “on duration” block 208, and DRX“on duration” block 210 represent times at which the DRX “on durationtimer” is on. In other words, each of blocks 206, 208, and 210 representtimes during which a UA is scheduled to receive resources and/or monitorthe PDCCH.

In the case illustrated at arrow 202, during which the downlink (DL) SPSis time aligned to the “on duration,” active time block 212, active timeblock 214, and active time block 216, are provided in order to representUA active time for receiving potential retransmission. DL SPStransmission block 218, DL SPS transmission block 220, and DL SPStransmission block 222 represent times of the configured DL assignments.

Arrow 202 shows that DL SPS transmission block 218 aligns with DRX “onduration” block 206, DL SPS transmission block 220 aligns with DRX “onduration” block 208, and DL SPS transmission block 222 aligns with DRX“on duration” block 210. Thus, the configured DL assignments are alignedto the DRX “on durations.” During these times, the UA receives SPStransmissions using the configured DL assignments, represented at DL SPStransmission blocks 218, 220, and 222.

Additionally, the UA starts the DRX retransmission timer. Starting theDRX retransmission timer means that the UA will be monitoring the PDCCHfor a configured duration, in order to receive a potentialretransmission after one round trip time. Active time block 212, activetime block 214, and active time block 216 show the UA active time forreceiving potential retransmission. Thus, in this case, the DL SPSoperates correctly.

However in the case illustrated at arrow 204, DL SPS transmission block224 does not align with DRX “on duration” block 206, DL SPS transmissionblock 226 does not align with DRX “on duration” block 208, and DL SPStransmission block 228 does not align with DRX “on duration” block 210.Thus, the configured DL assignments are not aligned to the DRX “ondurations.” For these blocks to be aligned, DL SPS transmission block226 should have been located at time block 230, and DL SPS transmissionblock 228 should have been located at time block 232.

In the current specifications (TS36.321 version 8.5.0), nothingrestricts the timing of when the network device (such as an eNB) canactivate DL SPS. The only requirement is that the UA be in active time,and therefore monitoring the PDCCH, in order to receive the SPSactivation command which configures downlink assignment. However, thenetwork device can choose to extend the active time in order to activateSPS at any time. Still further, when the DRX inactivity timer expires,such as at time instant 234 in FIG. 2, and the UA starts a DRXoperation, the UA may monitor the PDCCH only during “on duration” times.As a result, reception of DL SPS transmissions will cease to operatecorrectly, again as indicated at time block 226 and time block 228.

Based on the specifications in section 5.3.1 of TS36.321 version 8.5.0,the UA will not process the configured DL assignment in a subframe thatis not part of active time, the active time including a period of DRX“on duration” time. Thus, in FIG. 2, the UA will receive SPStransmissions using the configured downlink assignment 224 as it occursduring active time. However, the UA will not receive using theconfigured downlink assignments at time blocks 226 and 228, as theyoccur outside of active time. As a result, the SPS transmission will notbe received. This result may be inefficient and undesirable.

Furthermore, section 5.7 of TS36.321 version 8.5.0 specifies that the UAwill not start the HARQ RTT in a frame that is not part of active time.As a result, the UA may not be in active time and hence may not receivepotential retransmissions for downlink assignments configured outside of“on duration” time, which may cause further problems with the DL SPSoperation.

The present disclosure provides several embodiments related to theseissues. For example, for efficient radio resource utilization, oneembodiment provides that the UA may receive using a configured DLassignment independent of PDCCH monitoring. In another embodiment, theUA may monitor the PDCCH in a sub-frame in which DL assignment isconfigured. In still another embodiment, the DRX start offset can beadjusted to align with the configured resources. These and otherembodiments are described in more detail below.

FIG. 3 is a timing diagram illustrating simultaneous operation of SPSand DRX in a UA, according to an embodiment of the disclosure. Theprocedure shown in the timing diagram of FIG. 3 can be implemented in aUA, such as UA 102 of FIG. 1. Time moves along the direction shown byarrows 300 and 302, with times aligning along the various points of thetiming diagrams.

In the timing diagram of FIG. 3, the UA receives SPS transmissions usinga configured downlink assignment that is independent of active time.Thus, according to one embodiment, the UA may receive its SPStransmissions even if the assignment does not align with the “onduration” time. Accordingly, the UA has an extra occasion to be active,and the UA ultimately receives more transmissions. This technique canalso be implemented using the timing diagram shown in FIG. 4; however,the timing diagram with respect to FIG. 3 is described first.

Arrow 300 shows the DRX “on duration” timing. Thus, each of time blocks304, 306, and 308 show times that the DRX is “on duration.” Note thatthe SPS and DRX timings are not aligned.

Arrow 302 shows the UA activity. Time blocks 310, 312, and 314 show theactive times during the DRX “on duration.” Time blocks 316, 318, and 320show the active time for potential retransmissions. At time blocks 322,324, and 326, the UA is required to receive SPS transmissions using theconfigured DL assignment, even when not in active time. In this manner,the issues described with respect to FIG. 2 can be handledappropriately. Additionally, in an embodiment, the DRX retransmissiontimer can be started to allow for potential retransmission.

Accordingly, the UA uses a configured DL assignment to receive SPStransmissions independent of the UA monitoring the PDCCH. Thisembodiment provides for extending section 5.3.1 of TS36.321 version8.5.0, for example, such that when the UA has a C-RNTI, Semi-PersistentScheduling C-RNTI, or Temporary C-RNTI, the UA shall, for each TTIduring which it monitors PDCCH or to which a downlink assignment (oruplink grant) is configured, perform the specified procedures.Additionally, section 5.7 of TS36.321 version 8.5.0 might be modifiedaccording to one embodiment such that, during the Active Time and in asubframe to which a downlink assignment is configured, the UA willmonitor the PDCCH and follow the other specified procedures.

FIG. 4 is a timing diagram illustrating simultaneous operation of SPSand DRX in a UA, according to an embodiment of the disclosure. Theprocedure shown in the timing diagram of FIG. 4 can be implemented in aUA, such as UA 102 of FIG. 1. Time moves along the direction shown byarrows 400 and 402, with times aligning along the various points of thetiming diagrams. The timing diagrams shown in FIG. 4 represent analternative embodiment, relative to FIG. 3, relating to the issuespresented with respect to FIG. 2.

In the timing diagrams of FIG. 4, the UA is required to monitor thePDCCH during the configured downlink assignment, and to receive SPStransmissions using a configured DL assignment. Thus, according to oneembodiment, the UA may receive its SPS transmissions even if theassignment does not align with the “on duration” time. Accordingly, theUA has an extra occasion to be active, and the UA ultimately receivesmore transmissions. This technique can also be implemented using thetiming diagram shown in FIG. 3.

Arrow 400 shows the DRX “on duration” timing. Thus, each of time blocks404, 406, and 408 show times that the DRX is “on duration.” Note thatthe SPS and DRX timings are not aligned.

Arrow 402 shows the UA activity. Time blocks 410, 430, 432 show theactive time during the DRX “on duration.” Time blocks 412, 414, and 416show the active time for potential retransmissions. At time blocks 418,420, and 422, the UA is required to monitor the PDCCH during theconfigured downlink, and to receive SPS transmissions using a configuredDL assignment. Thus, time blocks 418, 420, and 422 become active times.In this manner, the issues described with respect to FIG. 2 areappropriately addressed. Additionally, in an embodiment, the DRXretransmission timer can be started to allow for potentialretransmission.

Accordingly, the UA monitors the PDCCH in a subframe to which a DLassignment is configured. This embodiment provides for extending section5.7 of TS36.321 version 8.5.0, for example, such that the active timeincludes a subframe to which a DL assignment is configured, in additionto the other times defined in the specification.

In some instances, this embodiment might be preferred over the firstembodiment described above (the UA using a configured DL assignment toreceive SPS transmissions independent of the UA monitoring the PDCCH)because the network device, such as an access device, might be able tooverride the configured DL assignment with a dynamically scheduled DLassignment. The DL assignment may be signaled on the PDCCH. This resultmight be useful, such as where the network device has extra data to sendto the UA, such as some ROHC (robust header compression) header contextinformation or ROHC feedback. However, in the former embodiment (FIG.3), the network device may not be able to override the configured DLassignment, and might have to send the additional data at the next “onduration” when the UA will be monitoring the PDCCH.

In the previous two embodiments (FIGS. 3 and 4), if the network device(such as an eNB) configures a DL assignment outside of the “on duration”period, the opportunity for DRX is reduced compared to the case wherethe configured resources are aligned with the DRX “on duration” period.For efficient UA battery usage, the DRX “start offset” could be adjustedto align when a DL assignment is configured or reconfigured. Thisembodiment is described with respect to FIG. 5, and may be implementedalone or in conjunction with the embodiments described with respect toFIGS. 3 and 4.

FIG. 5 is a timing diagram illustrating simultaneous operation of SPSand DRX in a UA, according to an embodiment of the disclosure. Theprocedure shown in the timing diagram of FIG. 5 can be implemented in aUA, such as UA 102 of FIG. 1. Time moves along the direction shown byarrows 500 and 502, with times aligning along the various points of thetiming diagrams. The timing diagrams shown in FIG. 5 represent anadditional and/or supplemental embodiment, relative to FIGS. 3 and 4,relating to the issues presented with respect to FIG. 2.

In the embodiment shown in FIG. 5, the UA adjusts the DRX “start offset”when a DL assignment is configured or reconfigured. In other words, theUA adjusts the DRX “start offset” when a SPS is activated. In theembodiment shown in FIG. 5, at arrow 502, SPS is initially notactivated.

Arrow 500 shows the DRX “on duration” timing. Thus, each of time blocks504, 506, 508, 510, and 512 show times that the DRX is “on duration.”Note that after the SPS is activated, the SPS and DRX timings areconfigured to be aligned.

Time block 514 represents the active time during the DRX “on duration.”This first time block aligns with the DRX “on duration” time block 504.

At time block 516, the network device (access node or eNB) extends theactive time beyond an expected time by sending data to the UA. At timeblock 518, the network device sends an SPS activation on the PDCCH usingSPS-RNTI. At this time, as shown at time block 508, the UA adjusts itsDRX timing to be aligned with timing of the SPS configured DLassignments. Accordingly, at time blocks 520 and 522, the DRX timing inthe UA is aligned with the DRX “on duration” times at time blocks 510and 512. Thus, the UA will receive SPS transmissions correctly. The UA'sactive times for potential retransmission occur at time blocks 524 and526.

Because no additional information is required, compared with SPSreinitializing messages on the PDCCH, the probability of a falsedetection is the same as compared to the current SPS activation. Thus,if an error occurs, such as if the UA missed the message on the PDCCH,the network device can revert back to the old DRX “start offset” valuefor error handling. Additionally, in this embodiment, the automaticadjustment of the DRX cycle timing promotes SPS and DRX timingalignment.

This embodiment can be implemented by using the procedure describedbelow along with the procedures currently proposed in section 5.10.1 ofTS36.321 version 8.5.0. In combination with the present disclosure, itwill be appreciated by one of ordinary skill in the art that backwardcompatibility ought to be considered. For example, in an embodiment, itmay be undesirable for the UA to adjust the DRX start offset asdisclosed herein when communicating with a legacy eNB, because legacyeNBs may not be expecting this adjustment, and because use of the DRXstart offset adjustment procedure when communicating with a legacy eNBmay result in the UA being unreachable by the legacy eNB. In anembodiment, an eNB designed to interoperate with the disclosed UA DRXstart offset adjustment procedures may employ RRC signaling to activateUA adjustment of the DRX start offset. In another embodiment, the eNBmay send a signal to activate UA adjustment of the DRX start offset byanother method or another protocol. In some contexts, it may be saidthat the eNB and/or access node is configured to transmit a DRX startadjust procedure activation signal via a radio resource control (RRC)protocol, for example to transmit the DRX start adjust procedureactivation signal via the RRC protocol to the UA.

If the DRX is configured, the UA may adjust the DRX “start offset” tosatisfy the following conditions. If the Short DRX Cycle is used, thenthe DRX start offset may be governed by the equation [(10*SFNstarttime+subframestart time)+N*(Downlink Semi-Persistent SchedulingInterval)] modulo (Short DRX Cycle)=(DRX start offset) modulo (Short DRXCycle). However, if the Long DRX Cycle is used, then the DRX startoffset may be governed by the equation [(10*SFNstart time+subframestarttime)+N*(Downlink Semi-Persistent Scheduling Interval)] modulo (Long DRXCycle)=DRX start offset. In the above equations, N is a positiveinteger.

Alternatively, in an embodiment, the DRX start offset may be reduced toshift the DRX slightly forward, to promote the SPS transmission beinginside the DRX “on duration” period. This shift forward of the DRX Cyclemay provide further flexibility for the access node packet schedulingfunction. If the Short DRX Cycle is used, then the DRX start offset maybe governed by the equation [(10*SFNstart time+subframestarttime)+N*(Downlink Semi-Persistent Scheduling Interval)] modulo (ShortDRX Cycle)=(DRX start offset) modulo (Short DRX Cycle)+timingAdjust.However, if the Long DRX Cycle is used, then the DRX start offset may begoverned by the equation [(10*SFNstart time+subframestarttime)+N*(Downlink Semi-Persistent Scheduling Interval)] modulo (Long DRXCycle)=(DRX start offset+timingAdjust). In the above equations, N is apositive integer and timingAdjust is a non-negative integer.

In an embodiment, the value of timingAdjust may be about one third theduration of the DRX “on duration” period. In another embodiment, thevalue of timingAdjust may be about one half the duration of the DRX “onduration” period. In an embodiment, timingAdjust may determined, forexample, astimingAdjust=Ceiling[DRX“on duration”/x]ortimingAdjust=Floor[DRX“on duration”/x]where x is a positive integer. In an embodiment, timingAdjust is lessthan the value of the DRX “on duration” time period. In anotherembodiment, the value of timingAdjust may be indicated by RRC protocol,for example carried along with a DRX start adjust procedure activationsignal.

In another embodiment, where the UA adjusts DRX “start offset” to theconfigured uplink grant, the UA may adjust the DRX “start offset” tosatisfy the following conditions. If the Short DRX Cycle is used, thenthe DRX start offset may be governed by the equation [(10*SFNstarttime+subframestart time)+N*(Downlink Semi-Persistent SchedulingInterval)+Subframe_Offset*(N modulo 2)] modulo (Short DRX Cycle)=(DRXstart offset) modulo (Short DRX Cycle). However, if the Long DRX Cycleis used, then the DRX start offset may be governed by the equation[(10*SFNstart time+subframestart time)+N (Downlink Semi-PersistentScheduling Interval)+Subframe_Offset*(N modulo 2)] modulo (Long DRXCycle)=DRX start offset. In the above equations, N is a positiveinteger.

Alternatively, in an embodiment, the DRX start offset may be reduced toshift the DRX slightly forward, to promote the SPS transmission beinginside the DRX “on duration” period. This shift forward of the DRX Cyclemay provide further flexibility for the access node packet schedulingfunction. If the Short DRX Cycle is used, then the DRX start offset maybe governed by the equation [(10*SFNstart time+subframestarttime)+N*(Downlink Semi-Persistent SchedulingInterval)+Subframe_Offset*(N modulo 2)] modulo (Short DRX Cycle)=(DRXstart offset) modulo (Short DRX Cycle)+timingAdjust. However, if theLong DRX Cycle is used, then the DRX start offset may be governed by theequation [(10*SFNstart time+subframestart time)+N*(DownlinkSemi-Persistent Scheduling Interval)+Subframe_Offset*(N modulo 2)]modulo (Long DRX Cycle)=(DRX start offset+timingAdjust). In the aboveequations, N is a positive integer and timingAdjust is a non-negativeinteger.

In an embodiment, the value of timingAdjust may be about one third theduration of the DRX “on duration” period. In another embodiment, thevalue of timingAdjust may be about one half the duration of the DRX “onduration” period. In an embodiment, timingAdjust may determined, forexample, astimingAdjust=Ceiling[DRX“on duration”/x]ortimingAdjust=Floor[DRX“on duration”/x]where x is a positive integer. In an embodiment, timingAdjust is lessthan the value of the DRX “on duration” time period. In anotherembodiment, the value of timingAdjust may be indicated by RRC protocol,for example carried along with a DRX start adjust procedure activationsignal.

In an embodiment, if the DRX is configured, the UA may adjust the DRX“start offset” to satisfy the following equation: (10*SFNstarttime+subframestart time) modulo (Long DRX Cycle)=DRX start offset.Alternatively, in an embodiment, the DRX “start offset” may be reducedto shift the DRX slightly forward, to promote the SPS transmission beinginside the DRX “on duration” period. This shift forward of the DRX Cyclemay provide further flexibility for the access node packet schedulingfunction. In this alternative embodiment, the UA may adjust the DRX“start offset” to satisfy the following equation: (10*SFNstarttime+subframestart time) modulo (Long DRX Cycle)=(DRX startoffset+timingAdjust). The appropriate range of values for thetimingAdjust are discussed further above.

With regards to alignment between configured uplink grant and DRX cycletiming, the network device may align the configuration of the uplinkgrant to the DRX start offset or configured DL assignment by adjustingwhen to configure an uplink grant, in order to save UA batteryconsumption. This alignment may occur when a new talkspurt starts.

In a further embodiment expanding on the procedure described withrespect to FIG. 5, the UA adjusting the “DRX start offset,” the UA maymonitor the PDCCH for the C-RNTI and SPS-RNTI during the “active time”to allow a change of DL assignment without restriction. Thus, forexample, a change of DL assignment may take place outside the “onduration” period.” In order to reduce false detection of SPS resourceactivation, or release over the PDCCH, the duration during which the UAmonitors the PDCCH for its SPS-RNTI may be reduced. The network devicemay indicate a change in configuration of downlink assignment in advanceby the PDCCH, MAC header, or MAC control element. If such an indicationis signaled, the UA will detect its SPS-RNTI during the “active time”for a preconfigured duration. Otherwise, the UA will detect its SPS-RNTIonly during the “on duration period.”

In still another embodiment relative to FIGS. 3 through 5, the “onduration” timer may be started or restarted when a starting condition issatisfied. Alternatively, in still another embodiment relative to FIGS.3 through 5, the “on duration” timer may be started or restarted when astarting condition is satisfied and when an on duration timerconfiguration activation signal is received via the radio resourcecontrol (RRC) protocol. This embodiment may be implemented in additionto any of the embodiments described with respect to FIGS. 3 through 5.This embodiment provides for appropriate DRX operation when the DRX“start offset” is adjusted as described above or reconfigured using RRCreconfiguration procedure.

FIG. 6 is a flowchart illustrating a method of receiving using aconfigured DL assignment, according to an embodiment of the disclosure.The procedure shown in FIG. 6 can be implemented in a UA, such as UA 102of FIG. 1.

The process begins by determining whether this TTI is part of an onactive time (block 600). If yes, then the UA promotes monitoring of thePDCCH (block 602). The UA then promotes receiving based on a downlinkassignment indicated by the PDCCH or a configured DL assignment (block604). The UA then determines whether to terminate (block 606).

If the process is not to terminate, then the process returns to block600. If the determination at block 600 was “no”, then the UA promotesdetermining whether this TTI is part of a configured DL assignment(block 608). If yes, then the process moves to block 604 and proceeds asdescribed above. If not, then the UA again determines whether to end atblock 606.

FIG. 7 is a flowchart illustrating a method of receiving using aconfigured DL assignment, according to an embodiment of the disclosure.The procedure shown in FIG. 7 can be implemented in a UA, such as UA 102of FIG. 1.

The process begins by determining whether this TTI is part of an onactive time (block 700). If so, then the UA promotes monitoring of thePDCCH (block 702). The UA then promotes determining whether this TTI ispart of a configured DL assignment (block 704). If so, then the UApromotes receiving based on a downlink assignment indicated by the PDCCHor a configured DL assignment (block 706).

Thereafter, or after a “no” determination at either block 700 or block704, the UA determines whether to end (block 708). If the process shouldcontinue, then the process returns to step 700 and repeats. Otherwise,the process terminates.

FIG. 8 is a flowchart illustrating a method of adjusting DRX timing andreceiving using a configured DL assignment, according to an embodimentof the disclosure. The procedure shown in FIG. 8 can be implemented in aUA, such as UA 102 of FIG. 1.

The process begins by determining whether this TTI is part of an onactive time (block 800). If so, then the UA promotes monitoring of thePDCCH (block 802). The UA then promotes determining whether the PDCCHindicates an SPS activation (block 804). If so, then the UA promotes achange in DRX timing such that it is aligned with the configured DLassignment received in the SPS activation (block 806).

Thereafter, or after a “no” determination at block 804, the UA promotesdetermining whether this TTI is part of a configured DL assignment. Ifso, then the UA promotes receiving based on a downlink assignmentindicated by the PDCCH or a configured DL assignment (block 810).

Thereafter, or after a “no” determination at either of blocks 800 or808, the UA determines whether to end (block 812). If the process shouldcontinue, then the process returns to step 800 and repeats. Otherwise,the process terminates.

FIG. 9 is a flowchart illustrating a method of adjusting DRX timing andreceiving using a configured DL assignment, according to an embodimentof the disclosure. The procedure shown in FIG. 9 can be implemented in aUA, such as UA 102 of FIG. 1.

The process begins as the UA determines if this TTI is part of an onactive time (block 900). If so, then the UA monitors the PDCCH (block902). The UA then determines whether the PDCCH indicates a downlinkassignment (block 904).

If the PDCCH does indicate a DL assignment, then the UA receivesaccording to the DL assignment indicated on the PDCCH (block 906).Thereafter, the UA determines whether to end the process (block 916). Ifthe process does not end, then the process returns to step 900 andrepeats. Otherwise, the process terminates.

Returning to block 904, if the PDCCH does not indicate a DL assignment,then the UA further determines whether the PDCCH indicates an SPSassignment (block 908). If the PDCCH does indicate a SPS assignment,then the UA changes the DRX timing to be aligned with the configured DLassignment received in the SPS activation (block 910). Thereafter, orafter a “no” determination at block 908, the UA determines whether toend the process. If the process does not end, then the process returnsto step 900 and repeats. Otherwise, the process terminates.

Returning to block 900, if this TTI is not part of an on active time,then the UA makes a determination whether this TTI is part of aconfigured downlink assignment (block 912). If this TTI is part of aconfigured DL assignment, then the UA receives using the configured DLassignment (block 914). Thereafter, or after a “no” determination atblock 912, the UA determines whether to end the process. If the processdoes not end, then the process returns to step 900 and repeats.Otherwise, the process terminates.

FIGS. 10 through 13 illustrate exemplary methods for implementing theembodiments described above. In each of the methods shown in FIGS. 10through 13, the corresponding method can be implemented in a UA or aneNB, such as UA 102 of FIG. 1. Each of these methods relate toaddressing a situation in which the UA receives a configured downlinkassignment outside of an active time, as shown in FIG. 2.

In particular, FIG. 10 is a flowchart illustrating a method ofconfiguring a downlink assignment, according to an embodiment of thedisclosure. The UA configures a downlink assignment independently ofmonitoring a physical downlink control channel according to indicationby a network node, such as an eNB (block 1000).

FIG. 11 is a flowchart illustrating a method of monitoring a physicaldownlink control channel (PDCCH), according to an embodiment of thedisclosure. The UA monitors a PDCCH in a subframe to which one of adownlink assignment and an uplink assignment grant is configured (block1100).

FIG. 12 is a flowchart illustrating a method of starting or restartingan on duration timer, according to an embodiment of the disclosure. TheUA performs one of starting and restarting an “on duration timer” when astarting condition is satisfied (block 1200). In an alternativeembodiment, the UA performs one of starting and restarting an “onduration timer” when a starting condition is satisfied and when a DRXstart adjust procedure activation signal is received, for examplereceived via a radio resource control (RRC) protocol.

FIG. 13 is a flowchart illustrating a method of adjusting adiscontinuous reception (DRX) start offset, according to an embodimentof the disclosure. The UA adjusts a DRX start offset when a downlinkassignment is one of configured and reconfigured by a network node, suchas an eNB (block 1300). Optionally, the UA may detect a SPS-RNTI duringan active time (block 1302). In an embodiment, the behavior depicted inFIG. 13 may be contingent on receiving a DRX start adjust procedureactivation signal, for example, but not by way of limitation, receivedvia a radio resource control (RRC) protocol. In an alternativeembodiment, the UA activates a DRX start adjust procedure when a DRXstart adjust procedure activation signal is received by the UA, forexample when the UA receives the DRX start adjust procedure activationsignal via a radio resource control (RRC) protocol.

In some cases the UA may falsely detect the activation of a SPS modewhen decoding the PDCCH and store the configured downlink assignment,for example when the UA receives the PDCCH in error and the CRC of thePDCCH agrees with the errored reception. In some circumstances, forexample, the false detection may be due to the limited length of the CRCon the PDCCH. Because the frequency resource indicated by the falselydetected SPS activation from which the UA receives and attempts todecode would be random, the decoding of the PDSCH subframes defined bythe false configured downlink assignment will fail considering thesufficient length of CRC (24 bits) is used for PDSCH transmission. As aresult, the UA will transmit NACKs consecutively. In othercircumstances, however, other conditions may result in and/or cause thefalse detection by the UA of the activation of the SPS mode.

In one embodiment, rather than adjusting the DRX “start offset”immediately when the UA detects activation of the SPS mode, as discussedabove with reference to FIG. 5, the UA may wait to adjust the DRX “startoffset” until the UA successfully decodes the one or more SPStransmissions on the PDSCH associated with the configured downlinkassignment, thereby confirming that the SPS activation was not receivedin error. In an embodiment, after the UA successfully decodes one ormore SPS transmissions on the PDSCH associated with the configureddownlink assignment within a number M downlink SPS intervals after thesubframe in which the UA receives the SPS activation command and storesthe configured downlink assignment for SPS transmissions, the UA mayconclude that the SPS activation was properly detected and may performprocessing going forwards on that assumption. In another embodiment,after the UA successfully decodes either one or more SPS transmissionson the PDSCH associated with the configured downlink assignment or oneor more SPS retransmissions on the PDSCH which are dynamically assignedby the PDCCH within a number M downlink SPS intervals after the subframein which the UA receives the SPS activation command and stores theconfigured downlink assignment for SPS transmissions, the UA mayconclude that the SPS activation was properly detected and may performprocessing going forwards on that assumption. For example, in anembodiment, the UA may adjust the DRX “start offset” to coincide withthe SPS at the last subframe of the Mth downlink SPS interval after thesubframe in which the UA receives the SPS activation command and storesthe configured downlink assignment. In an embodiment the eNB mayconclude that SPS activation is successful and may perform processinggoing forwards on that assumption if one or more ACKs response to SPStransmissions or SPS retransmissions are received within the M downlinkSPS intervals after the subframe in which the eNB transmits the SPSactivation command. For example, in an embodiment, the eNB may adjustthe DRX “start offset” to coincide with the SPS at the last subframe ofthe Mth downlink SPS interval after the subframe in which the eNBtransmits the SPS activation command. In an embodiment, the number M mayone of two, three, and four. In another embodiment, the number M may bein the range from four to ten. In yet another embodiment, the number Mmay be another value. In yet another embodiment, M may be specified innumber of subframes. For example, M is N*(downlink SPS interval insubframe) where N may be a positive integer. M may be a predefined valueor may be signaled by RRC.

In another embodiment, the UA may adjust the DRX “start offset”immediately when the UA detects activation of the SPS mode (but detectsSPS activation in error, for example because of a low received signalstrength, because of radio interference, or because of some otherimpairment of transmission, reception, and/or propagation), as discussedabove with reference to FIG. 5. After the UA detects a number Nconsecutive failed decodings of the SPS transmissions on the PDSCHassociated with the configured downlink assignment, the UA may concludethat the SPS activation was falsely detected and perform processinggoing forwards on that assumption. In another embodiment after the UAdetects a number N consecutive failed decodings of either the SPStransmissions on the PDSCH associated with the configured downlinkassignment or the SPS retransmissions on the PDSCH dynamically assignedby PDCCH, the UA may conclude that the SPS activation was falselydetected and perform processing going forwards on that assumption. Inanother embodiment, after UA does not decode any SPS transmissions onPDSCH associated with the configured downlink assignment within acertain duration M after the subframe in which the UA receives the SPSactivation and stores the configured downlink assignment, the UA mayconclude that the SPS activation was falsely detected and performprocessing going forwards on that assumption. For example the durationmay be in a number of subframes or a number of downlink SPS intervals.In yet another embodiment, after UA does not decode any of either SPStransmissions on the PDSCH associated with the configured downlinkassignment or SPS retransmissions on the PDSCH dynamically assigned byPDCCH within a certain duration M after the subframe in which the UAreceives the SPS activation and stores the configured downlinkassignment, the UA may conclude that the SPS activation was falselydetected and perform processing going forwards on that assumption. Forexample the duration may be in a number of subframes or a number ofdownlink SPS intervals or a predefined time duration. For example, in anembodiment, if the UA reaches a conclusion that the SPS activation wasfalsely detected, the UA may revert to the DRX timing before adoptingthe DRX “start offset” as described with reference to FIG. 5 above. Inan embodiment, the number N may be one of one, two, and three. Inanother embodiment, the number N may be between four and ten, inclusiveof four and ten. In yet another embodiment, the number N may be betweeneleven and twenty, inclusive of eleven and twenty. In anotherembodiment, the number N may be another value. N may be a predefinedvalue or may be signaled by RRC. In an embodiment M may one of two,three, and four downlink SPS intervals. In another embodiment, thenumber M may be in the range from four to ten. In yet anotherembodiment, the number M may be another value. In yet anotherembodiment, M may be specified in number of subframes. For example, M isN*(downlink SPS interval in subframe) where N may be a positive integer.M may be a predefined value or may be signaled by RRC.

In another embodiment, the eNB may determine that the UA has falselydetected activation of the SPS mode, for example by determining that theUA repeatedly transmits consecutive NACKs. The uplink resource for HARQfeedback to SPS transmission is configured by RRC. Therefore the eNB maybe able to identify the UA consecutively transmitting NACKs by theuplink resources used to transmit the NACKs if a single PUCCH resourceindex is used for SPS configuration. If multiple PUCCH resource indexesare used for a UA, the eNB may identify multiple UAs. In an embodiment,the eNB may remedy the false detection of the SPS activation by the UAby transmitting an SPS activation message to the UA or multiple UAswithin the Active Time which can be calculated by the time when theNACKs are received in order to correct the misbehavior resulting fromthe false detection by the UA of the SPS activation. In an embodiment,the eNB may determine that a number N consecutive NACKs received fromthe UA indicates the UA has falsely detected activation of the SPS mode.In an embodiment, the number N may be one of one, two, three, and four.In another embodiment, the number N may be in the range from four toten, inclusive of four and ten. In yet another embodiment, the number Nmay be some other value. The embodiments described in this paragraphalso can be applied to remedy the case where the SPS activation wascorrectly received by the UA, and the UA changes the DRX “start offset,”but the eNB fails to receive ACK or NACK from the UA and maintains thecurrent DRX “start offset.”

Another error may occur in the SPS activation: in some circumstances,the eNB may activate the SPS mode via the PDCCH, but the UA may fail toreceive the activation, the eNB erroneously detects ACK or NACK andstarts scheduling subsequent SPS transmissions. In this circumstance,the eNB may detect this condition by observing that the UA does notprovide any HARQ feedbacks—neither ACKs or NACKS. The eNB may conclude,on this basis, that the UA has not activated the SPS mode, and the eNBmay retransmit the SPS activation during the DRX period based on thealready configured DRX “start offset.” In an embodiment, the eNB mayconclude that the UA has not activated the SPS mode after receiving noHARQ feedback from the UA for a number M consecutive subframetransmissions to the UA. In an embodiment, the number M may be one ofone, two, three, and four. In another embodiment, the number M may be inthe range from five to ten, inclusive of five and ten. In yet anotherembodiment, some M may be some other number.

The UA and other components described above might include a processingcomponent that is capable of executing instructions related to theactions described above. FIG. 14 illustrates an example of a system 1400that includes a processing component 1410 suitable for implementing oneor more embodiments disclosed herein. In addition to the processor 1410(which may be referred to as a central processor unit or CPU), thesystem 1400 might include network connectivity devices 1420, randomaccess memory (RAM) 1430, read only memory (ROM) 1440, secondary storage1450, and input/output (I/O) devices 1460. These components mightcommunicate with one another via a bus 1470. In some cases, some ofthese components may not be present or may be combined in variouscombinations with one another or with other components not shown. Thesecomponents might be located in a single physical entity or in more thanone physical entity. Any actions described herein as being taken by theprocessor 1410 might be taken by the processor 1410 alone or by theprocessor 1410 in conjunction with one or more components shown or notshown in the drawing, such as a digital signal processor (DSP) 1490.Although the DSP 1490 is shown as a separate component, the DSP 1490might be incorporated into the processor 1410.

The processor 1410 executes instructions, codes, computer programs, orscripts that it might access from the network connectivity devices 1420,RAM 1430, ROM 1440, or secondary storage 1450 (which might includevarious disk-based systems such as hard disk, floppy disk, or opticaldisk). While only one CPU 1410 is shown, multiple processors may bepresent. Thus, while instructions may be discussed as being executed bya processor, the instructions may be executed simultaneously, serially,or otherwise by one or multiple processors. The processor 1410 may beimplemented as one or more CPU chips.

The network connectivity devices 1420 may take the form of modems, modembanks, Ethernet devices, universal serial bus (USB) interface devices,serial interfaces, token ring devices, fiber distributed data interface(FDDI) devices, wireless local area network (WLAN) devices, radiotransceiver devices such as code division multiple access (CDMA)devices, global system for mobile communications (GSM) radio transceiverdevices, worldwide interoperability for microwave access (WiMAX)devices, and/or other well-known devices for connecting to networks.These network connectivity devices 1420 may enable the processor 1410 tocommunicate with the Internet or one or more telecommunications networksor other networks from which the processor 1410 might receiveinformation or to which the processor 1410 might output information. Thenetwork connectivity devices 1420 might also include one or moretransceiver components 1425 capable of transmitting and/or receivingdata wirelessly.

The RAM 1430 might be used to store volatile data and perhaps to storeinstructions that are executed by the processor 1410. The ROM 1440 is anon-volatile memory device that typically has a smaller memory capacitythan the memory capacity of the secondary storage 1450. ROM 1440 mightbe used to store instructions and perhaps data that are read duringexecution of the instructions. Access to both RAM 1430 and ROM 1440 istypically faster than to secondary storage 1450. The secondary storage1450 is typically comprised of one or more disk drives or tape drivesand might be used for non-volatile storage of data or as an over-flowdata storage device if RAM 1430 is not large enough to hold all workingdata. Secondary storage 1450 may be used to store programs that areloaded into RAM 1430 when such programs are selected for execution.

The I/O devices 1460 may include liquid crystal displays (LCDs), touchscreen displays, keyboards, keypads, switches, dials, mice, track balls,voice recognizers, card readers, paper tape readers, printers, videomonitors, or other well-known input/output devices. Also, thetransceiver 1425 might be considered to be a component of the I/Odevices 1460 instead of or in addition to being a component of thenetwork connectivity devices 1420.

The following are incorporated herein by reference for all purposes: 3rdGeneration Partnership Project (3GPP) Technical Specification (TS)24.008, 25.331, 36.321, 36.33, 36.211, R2-086815 “Clarification of DRXActive Time” Ericsson, InterDigital, Nokia, NSN, Sunplus, as well asR2-090820 “RRC Processing Delay” Qualcomm.

U.S. provisional patent application Ser. No. 61/162,594 filed Mar. 23,2009, by Takashi Suzuki et al., entitled “Discontinuous Reception andSemi-Persistent Scheduling and Alignment System and Method” is herebyincorporated by reference for all purposes.

In an embodiment, a user agent is disclosed. The user agent comprises aprocessor enabled to configure the user agent to adjust a discontinuousreception (DRX) start offset when a downlink assignment is one ofconfigured and reconfigured. The DRX start offset is adjusted to satisfythe equation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset

In another embodiment, a user agent is disclosed. The user agentcomprises a processor enabled to configure the user agent to adjust adiscontinuous reception (DRX) start offset when a downlink assignment isone of configured and reconfigured. The DRX start offset is adjusted tosatisfy the equation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset+timingAdjust

In another embodiment, a method implemented in a user agent isdisclosed. The method comprises adjusting a discontinuous reception(DRX) start offset when a downlink assignment is one of configured andreconfigured. The DRX start offset is adjusted to satisfy the equation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset

In another embodiment, a method implemented in a user agent isdisclosed. The method comprises adjusting a discontinuous reception(DRX) start offset when a downlink assignment is one of configured andreconfigured. The DRX start offset is adjusted to satisfy the equation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset+timingAdjust

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

Also, techniques, systems, subsystems and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component, whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. A user agent, comprising: a storage devicecomprising instructions executable by a processor, the instructionsconfigured such that when executed, cause the processor to adjust adiscontinuous reception (DRX) start offset when a semi-persistentscheduling (SPS) downlink assignment is configured or reconfigured, theDRX start offset adjusted to promote using the downlink assignmentduring DRX operation, wherein the DRX start offset is adjusted such thatSPS transmissions align in time with an “on duration” of a DRX cycle. 2.The user agent of claim 1, wherein the user agent is configured tomonitor a physical downlink control channel (PDCCH) during the“duration” of each DRX cycle.
 3. The user agent of claim 2, wherein theDRX start offset is adjusted to satisfy the equation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset+timingAdjust, where SFNstart time corresponds to a system framenumber (SFN).
 4. The user agent of claim 3, where the value oftimingAdjust is less than or equal to one half of the DRX “on duration”.5. The user agent of claim 2, wherein the user agent is configured todetect a SPS radio network temporary identifier (RNTI) during one of the“on duration” or an active time in which the user agent monitors aphysical downlink control channel (PDCCH).
 6. The user agent of claim 5,wherein the user agent only attempts detecting the SPS RNTI during the“on duration” unless the user agent receives an indication from anaccess node to monitor the PDCCH during the active time for apreconfigured duration.
 7. A method implemented in a user agent, themethod comprising: adjusting a discontinuous reception (DRX) startoffset when a semi-persistent scheduling (SPS) downlink assignment isconfigured or reconfigured, the DRX start offset adjusted to promoteusing the downlink assignment during DRX operation, wherein the DRXstart offset is adjusted such that SPS transmissions align in time withan “on duration” of a DRX cycle.
 8. The method of claim 7, wherein theuser agent is configured to monitor a physical downlink control channel(PDCCH) during the “on duration” of each DRX cycle.
 9. The method ofclaim 8, wherein the DRX start offset is adjusted to satisfy theequation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset+timingAdjust, where SFNstart time corresponds to a system framenumber (SFN).
 10. The method of claim 9, where the value of timingAdjustis less than or equal to one half of the DRX “on duration”.
 11. Themethod of claim 8, further comprising attempting to detect a SPS radionetwork temporary identifier (RNTI) during one of the “on duration” oran active time in which the user agent monitors a physical downlinkcontrol channel (PDCCH).
 12. The method of claim 11, wherein the useragent only attempts detecting the SPS RNTI during the “on duration”unless the user agent receives an indication from an access node tomonitor the PDCCH during the active time for a preconfigured duration.13. The non-transitory computer medium storing computer readableinstructions executable by a processor to implement a method in a useragent, the method comprising: adjusting a discontinuous reception (DRX)start offset when a semi-persistent scheduling (SPS) downlink assignmentis configured or reconfigured, the DRX start offset adjusted to promoteusing the downlink assignment during DRX operation, wherein the DRXstart offset is adjusted such that SPS transmissions align in the withan “on duration” of a DRX cycle.
 14. The non-transitory computer mediumof claim 13, wherein the user agent is configured to monitor a physicaldownlink control channel (PDCCH) during the “on duration” of each DRXcycle.
 15. The non-transitory computer medium of claim 14, wherein theDRX start offset is adjusted to satisfy the equation:(10*SFNstart time+subframestart time)modulo(Long DRX Cycle)=DRX startoffset+timingAdjust, where SFNstart time corresponds to a system framenumber (SFN).
 16. The non-transitory computer medium of claim 15, wherethe value of timingAdjust is less than or equal to one half of the DRX“on duration”.
 17. The non-transitory computer medium of claim 14,wherein the method further comprises attempting to detect a SPS radionetwork temporary identifier (RNTI) during one of the “on duration” oran active time in which the user agent monitors a physical downlinkcontrol channel (PDCCH).
 18. The non-transitory computer medium of claim17, wherein the user agent only attempts detecting the SPS RNTI duringthe “on duration” unless the user agent receives an indication from anaccess node to monitor the PDCCH during the active time for apreconfigured duration.
 19. The user agent of claim 2, wherein the useragent does not monitor the PDCCH outside the “on duration” unless theuser agent receives an indication from an access node to monitor thePDCCH for a preconfigured duration.
 20. The user agent of claim 1,wherein the DRX start offset is adjusted to ensure that the downlinkassignment periodically recurs in subframes coinciding with the “onduration” of each DRX cycle, and wherein the user agent is configured touse the downlink assignment for SPS transmissions in the subframescoinciding with the “on duration” of each DRX cycle.